The objective of this research program is to elucidate the patterns of chemical reactivity of metal ions coordinated to macrocyclic tetradentate ligands. The emphasis of the research program will be on the mechanisms of stoichiometrically simple chemical reaction. The major areas of research will involve: (1) studies of the chemical reactivity and the nature of the bonding in cobalt-alkyl compounds: (2) studies of oxidation-reduction chemistry in covalently linked binuclear macrocyclic complexes; (3) studies designed to probed fundamental aspects of electron transfer and other redox reaction in constrained systems. A prevailing philosophy of much of this work will be to search for patterns or trends in reactivity in the reactions of simple synthetic complexes which contain selected structural features of prosthetic groups in metalloenzymes.